Dr. Jekyll No. 1, Formaldehyde-free lith developer I've been wanting to do lith printing for a while, but I've been discouraged by the use of formaldehyde in the developers, since my darkroom is poorly ventilated.
I know now there are some lith developers that are free of formaldehyde, like Moersch SE5, and that acetone is a possible replacement. However, reading comments by David Soemarko on a message board I'm now unable to find, I figured it would be possible to mix up a developer that doesn't use either of the organic compounds, just standard chemicals.
Formaldehyde's job in the developer, as I understand it, is to bond with sulfite and keep the level of free sulfite low. Too much free sulfite inhibits infectious development, the working principle of a lith developer. However, some sulfite is needed to activate the hydroquinone. So the trick to making a formaldehyde-free developer is merely to keep sulfite low.
Dr. Jekyll No. 1
1l water, room temperature
16g Sodium carbonate monohydrate (Arm & Hammer Washing soda)
a pinch of sodium sulfite (about 0.5g)
4g hydroquinone
4g potassium bromide
Dissolve in the order given, and use immediately - it will not keep. It will lith fine from the first print (tested on Forte Polywarmtone), but only lasts for three prints or so. Then it's time to pitch it out and mix anew. That sounds wasteful, but note that the components are cheap, and you can prepare several batches of powder ahead of time.
I haven't figured out how to replenish it. I had hoped that I could reinvigorate it by adding small amounts of hydroquinone and sulfite, but that doesn't work. They will restore activity, but the developer then starts producing horrible streaks. Don't save any Old Brown when mixing new - that will ensure that streaking continues.
Input on how to improve this are welcome!
Oh, and it's Dr. Jekyll because it leaves out the 'hyde. :-) |